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Diffstat (limited to 'src/lua/lcode.c')
| -rw-r--r-- | src/lua/lcode.c | 1203 |
1 files changed, 1203 insertions, 0 deletions
diff --git a/src/lua/lcode.c b/src/lua/lcode.c new file mode 100644 index 0000000..37adc6d --- /dev/null +++ b/src/lua/lcode.c @@ -0,0 +1,1203 @@ +/* +** $Id: lcode.c,v 2.112.1.1 2017/04/19 17:20:42 roberto Exp $ +** Code generator for Lua +** See Copyright Notice in lua.h +*/ + +#define lcode_c +#define LUA_CORE + +#include "lprefix.h" + + +#include "math.h" +#include "stdlib.h" + +#include "lua.h" + +#include "lcode.h" +#include "ldebug.h" +#include "ldo.h" +#include "lgc.h" +#include "llex.h" +#include "lmem.h" +#include "lobject.h" +#include "lopcodes.h" +#include "lparser.h" +#include "lstring.h" +#include "ltable.h" +#include "lvm.h" + + +/* Maximum number of registers in a Lua function (must fit in 8 bits) */ +#define MAXREGS 255 + + +#define hasjumps(e) ((e)->t != (e)->f) + + +/* +** If expression is a numeric constant, fills 'v' with its value +** and returns 1. Otherwise, returns 0. +*/ +static int tonumeral(const expdesc *e, TValue *v) { + if (hasjumps(e)) + return 0; /* not a numeral */ + switch (e->k) { + case VKINT: + if (v) setivalue(v, e->u.ival); + return 1; + case VKFLT: + if (v) setfltvalue(v, e->u.nval); + return 1; + default: return 0; + } +} + + +/* +** Create a OP_LOADNIL instruction, but try to optimize: if the previous +** instruction is also OP_LOADNIL and ranges are compatible, adjust +** range of previous instruction instead of emitting a new one. (For +** instance, 'local a; local b' will generate a single opcode.) +*/ +void luaK_nil (FuncState *fs, int from, int n) { + Instruction *previous; + int l = from + n - 1; /* last register to set nil */ + if (fs->pc > fs->lasttarget) { /* no jumps to current position? */ + previous = &fs->f->code[fs->pc-1]; + if (GET_OPCODE(*previous) == OP_LOADNIL) { /* previous is LOADNIL? */ + int pfrom = GETARG_A(*previous); /* get previous range */ + int pl = pfrom + GETARG_B(*previous); + if ((pfrom <= from && from <= pl + 1) || + (from <= pfrom && pfrom <= l + 1)) { /* can connect both? */ + if (pfrom < from) from = pfrom; /* from = min(from, pfrom) */ + if (pl > l) l = pl; /* l = max(l, pl) */ + SETARG_A(*previous, from); + SETARG_B(*previous, l - from); + return; + } + } /* else go through */ + } + luaK_codeABC(fs, OP_LOADNIL, from, n - 1, 0); /* else no optimization */ +} + + +/* +** Gets the destination address of a jump instruction. Used to traverse +** a list of jumps. +*/ +static int getjump (FuncState *fs, int pc) { + int offset = GETARG_sBx(fs->f->code[pc]); + if (offset == NO_JUMP) /* point to itself represents end of list */ + return NO_JUMP; /* end of list */ + else + return (pc+1)+offset; /* turn offset into absolute position */ +} + + +/* +** Fix jump instruction at position 'pc' to jump to 'dest'. +** (Jump addresses are relative in Lua) +*/ +static void fixjump (FuncState *fs, int pc, int dest) { + Instruction *jmp = &fs->f->code[pc]; + int offset = dest - (pc + 1); + lua_assert(dest != NO_JUMP); + if (abs(offset) > MAXARG_sBx) + luaX_syntaxerror(fs->ls, "control structure too long"); + SETARG_sBx(*jmp, offset); +} + + +/* +** Concatenate jump-list 'l2' into jump-list 'l1' +*/ +void luaK_concat (FuncState *fs, int *l1, int l2) { + if (l2 == NO_JUMP) return; /* nothing to concatenate? */ + else if (*l1 == NO_JUMP) /* no original list? */ + *l1 = l2; /* 'l1' points to 'l2' */ + else { + int list = *l1; + int next; + while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */ + list = next; + fixjump(fs, list, l2); /* last element links to 'l2' */ + } +} + + +/* +** Create a jump instruction and return its position, so its destination +** can be fixed later (with 'fixjump'). If there are jumps to +** this position (kept in 'jpc'), link them all together so that +** 'patchlistaux' will fix all them directly to the final destination. +*/ +int luaK_jump (FuncState *fs) { + int jpc = fs->jpc; /* save list of jumps to here */ + int j; + fs->jpc = NO_JUMP; /* no more jumps to here */ + j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP); + luaK_concat(fs, &j, jpc); /* keep them on hold */ + return j; +} + + +/* +** Code a 'return' instruction +*/ +void luaK_ret (FuncState *fs, int first, int nret) { + luaK_codeABC(fs, OP_RETURN, first, nret+1, 0); +} + + +/* +** Code a "conditional jump", that is, a test or comparison opcode +** followed by a jump. Return jump position. +*/ +static int condjump (FuncState *fs, OpCode op, int A, int B, int C) { + luaK_codeABC(fs, op, A, B, C); + return luaK_jump(fs); +} + + +/* +** returns current 'pc' and marks it as a jump target (to avoid wrong +** optimizations with consecutive instructions not in the same basic block). +*/ +int luaK_getlabel (FuncState *fs) { + fs->lasttarget = fs->pc; + return fs->pc; +} + + +/* +** Returns the position of the instruction "controlling" a given +** jump (that is, its condition), or the jump itself if it is +** unconditional. +*/ +static Instruction *getjumpcontrol (FuncState *fs, int pc) { + Instruction *pi = &fs->f->code[pc]; + if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1)))) + return pi-1; + else + return pi; +} + + +/* +** Patch destination register for a TESTSET instruction. +** If instruction in position 'node' is not a TESTSET, return 0 ("fails"). +** Otherwise, if 'reg' is not 'NO_REG', set it as the destination +** register. Otherwise, change instruction to a simple 'TEST' (produces +** no register value) +*/ +static int patchtestreg (FuncState *fs, int node, int reg) { + Instruction *i = getjumpcontrol(fs, node); + if (GET_OPCODE(*i) != OP_TESTSET) + return 0; /* cannot patch other instructions */ + if (reg != NO_REG && reg != GETARG_B(*i)) + SETARG_A(*i, reg); + else { + /* no register to put value or register already has the value; + change instruction to simple test */ + *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i)); + } + return 1; +} + + +/* +** Traverse a list of tests ensuring no one produces a value +*/ +static void removevalues (FuncState *fs, int list) { + for (; list != NO_JUMP; list = getjump(fs, list)) + patchtestreg(fs, list, NO_REG); +} + + +/* +** Traverse a list of tests, patching their destination address and +** registers: tests producing values jump to 'vtarget' (and put their +** values in 'reg'), other tests jump to 'dtarget'. +*/ +static void patchlistaux (FuncState *fs, int list, int vtarget, int reg, + int dtarget) { + while (list != NO_JUMP) { + int next = getjump(fs, list); + if (patchtestreg(fs, list, reg)) + fixjump(fs, list, vtarget); + else + fixjump(fs, list, dtarget); /* jump to default target */ + list = next; + } +} + + +/* +** Ensure all pending jumps to current position are fixed (jumping +** to current position with no values) and reset list of pending +** jumps +*/ +static void dischargejpc (FuncState *fs) { + patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc); + fs->jpc = NO_JUMP; +} + + +/* +** Add elements in 'list' to list of pending jumps to "here" +** (current position) +*/ +void luaK_patchtohere (FuncState *fs, int list) { + luaK_getlabel(fs); /* mark "here" as a jump target */ + luaK_concat(fs, &fs->jpc, list); +} + + +/* +** Path all jumps in 'list' to jump to 'target'. +** (The assert means that we cannot fix a jump to a forward address +** because we only know addresses once code is generated.) +*/ +void luaK_patchlist (FuncState *fs, int list, int target) { + if (target == fs->pc) /* 'target' is current position? */ + luaK_patchtohere(fs, list); /* add list to pending jumps */ + else { + lua_assert(target < fs->pc); + patchlistaux(fs, list, target, NO_REG, target); + } +} + + +/* +** Path all jumps in 'list' to close upvalues up to given 'level' +** (The assertion checks that jumps either were closing nothing +** or were closing higher levels, from inner blocks.) +*/ +void luaK_patchclose (FuncState *fs, int list, int level) { + level++; /* argument is +1 to reserve 0 as non-op */ + for (; list != NO_JUMP; list = getjump(fs, list)) { + lua_assert(GET_OPCODE(fs->f->code[list]) == OP_JMP && + (GETARG_A(fs->f->code[list]) == 0 || + GETARG_A(fs->f->code[list]) >= level)); + SETARG_A(fs->f->code[list], level); + } +} + + +/* +** Emit instruction 'i', checking for array sizes and saving also its +** line information. Return 'i' position. +*/ +static int luaK_code (FuncState *fs, Instruction i) { + Proto *f = fs->f; + dischargejpc(fs); /* 'pc' will change */ + /* put new instruction in code array */ + luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction, + MAX_INT, "opcodes"); + f->code[fs->pc] = i; + /* save corresponding line information */ + luaM_growvector(fs->ls->L, f->lineinfo, fs->pc, f->sizelineinfo, int, + MAX_INT, "opcodes"); + f->lineinfo[fs->pc] = fs->ls->lastline; + return fs->pc++; +} + + +/* +** Format and emit an 'iABC' instruction. (Assertions check consistency +** of parameters versus opcode.) +*/ +int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) { + lua_assert(getOpMode(o) == iABC); + lua_assert(getBMode(o) != OpArgN || b == 0); + lua_assert(getCMode(o) != OpArgN || c == 0); + lua_assert(a <= MAXARG_A && b <= MAXARG_B && c <= MAXARG_C); + return luaK_code(fs, CREATE_ABC(o, a, b, c)); +} + + +/* +** Format and emit an 'iABx' instruction. +*/ +int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) { + lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx); + lua_assert(getCMode(o) == OpArgN); + lua_assert(a <= MAXARG_A && bc <= MAXARG_Bx); + return luaK_code(fs, CREATE_ABx(o, a, bc)); +} + + +/* +** Emit an "extra argument" instruction (format 'iAx') +*/ +static int codeextraarg (FuncState *fs, int a) { + lua_assert(a <= MAXARG_Ax); + return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a)); +} + + +/* +** Emit a "load constant" instruction, using either 'OP_LOADK' +** (if constant index 'k' fits in 18 bits) or an 'OP_LOADKX' +** instruction with "extra argument". +*/ +int luaK_codek (FuncState *fs, int reg, int k) { + if (k <= MAXARG_Bx) + return luaK_codeABx(fs, OP_LOADK, reg, k); + else { + int p = luaK_codeABx(fs, OP_LOADKX, reg, 0); + codeextraarg(fs, k); + return p; + } +} + + +/* +** Check register-stack level, keeping track of its maximum size +** in field 'maxstacksize' +*/ +void luaK_checkstack (FuncState *fs, int n) { + int newstack = fs->freereg + n; + if (newstack > fs->f->maxstacksize) { + if (newstack >= MAXREGS) + luaX_syntaxerror(fs->ls, + "function or expression needs too many registers"); + fs->f->maxstacksize = cast_byte(newstack); + } +} + + +/* +** Reserve 'n' registers in register stack +*/ +void luaK_reserveregs (FuncState *fs, int n) { + luaK_checkstack(fs, n); + fs->freereg += n; +} + + +/* +** Free register 'reg', if it is neither a constant index nor +** a local variable. +) +*/ +static void freereg (FuncState *fs, int reg) { + if (!ISK(reg) && reg >= fs->nactvar) { + fs->freereg--; + lua_assert(reg == fs->freereg); + } +} + + +/* +** Free register used by expression 'e' (if any) +*/ +static void freeexp (FuncState *fs, expdesc *e) { + if (e->k == VNONRELOC) + freereg(fs, e->u.info); +} + + +/* +** Free registers used by expressions 'e1' and 'e2' (if any) in proper +** order. +*/ +static void freeexps (FuncState *fs, expdesc *e1, expdesc *e2) { + int r1 = (e1->k == VNONRELOC) ? e1->u.info : -1; + int r2 = (e2->k == VNONRELOC) ? e2->u.info : -1; + if (r1 > r2) { + freereg(fs, r1); + freereg(fs, r2); + } + else { + freereg(fs, r2); + freereg(fs, r1); + } +} + + +/* +** Add constant 'v' to prototype's list of constants (field 'k'). +** Use scanner's table to cache position of constants in constant list +** and try to reuse constants. Because some values should not be used +** as keys (nil cannot be a key, integer keys can collapse with float +** keys), the caller must provide a useful 'key' for indexing the cache. +*/ +static int addk (FuncState *fs, TValue *key, TValue *v) { + lua_State *L = fs->ls->L; + Proto *f = fs->f; + TValue *idx = luaH_set(L, fs->ls->h, key); /* index scanner table */ + int k, oldsize; + if (ttisinteger(idx)) { /* is there an index there? */ + k = cast_int(ivalue(idx)); + /* correct value? (warning: must distinguish floats from integers!) */ + if (k < fs->nk && ttype(&f->k[k]) == ttype(v) && + luaV_rawequalobj(&f->k[k], v)) + return k; /* reuse index */ + } + /* constant not found; create a new entry */ + oldsize = f->sizek; + k = fs->nk; + /* numerical value does not need GC barrier; + table has no metatable, so it does not need to invalidate cache */ + setivalue(idx, k); + luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants"); + while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]); + setobj(L, &f->k[k], v); + fs->nk++; + luaC_barrier(L, f, v); + return k; +} + + +/* +** Add a string to list of constants and return its index. +*/ +int luaK_stringK (FuncState *fs, TString *s) { + TValue o; + setsvalue(fs->ls->L, &o, s); + return addk(fs, &o, &o); /* use string itself as key */ +} + + +/* +** Add an integer to list of constants and return its index. +** Integers use userdata as keys to avoid collision with floats with +** same value; conversion to 'void*' is used only for hashing, so there +** are no "precision" problems. +*/ +int luaK_intK (FuncState *fs, lua_Integer n) { + TValue k, o; + setpvalue(&k, cast(void*, cast(size_t, n))); + setivalue(&o, n); + return addk(fs, &k, &o); +} + +/* +** Add a float to list of constants and return its index. +*/ +static int luaK_numberK (FuncState *fs, lua_Number r) { + TValue o; + setfltvalue(&o, r); + return addk(fs, &o, &o); /* use number itself as key */ +} + + +/* +** Add a boolean to list of constants and return its index. +*/ +static int boolK (FuncState *fs, int b) { + TValue o; + setbvalue(&o, b); + return addk(fs, &o, &o); /* use boolean itself as key */ +} + + +/* +** Add nil to list of constants and return its index. +*/ +static int nilK (FuncState *fs) { + TValue k, v; + setnilvalue(&v); + /* cannot use nil as key; instead use table itself to represent nil */ + sethvalue(fs->ls->L, &k, fs->ls->h); + return addk(fs, &k, &v); +} + + +/* +** Fix an expression to return the number of results 'nresults'. +** Either 'e' is a multi-ret expression (function call or vararg) +** or 'nresults' is LUA_MULTRET (as any expression can satisfy that). +*/ +void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) { + if (e->k == VCALL) { /* expression is an open function call? */ + SETARG_C(getinstruction(fs, e), nresults + 1); + } + else if (e->k == VVARARG) { + Instruction *pc = &getinstruction(fs, e); + SETARG_B(*pc, nresults + 1); + SETARG_A(*pc, fs->freereg); + luaK_reserveregs(fs, 1); + } + else lua_assert(nresults == LUA_MULTRET); +} + + +/* +** Fix an expression to return one result. +** If expression is not a multi-ret expression (function call or +** vararg), it already returns one result, so nothing needs to be done. +** Function calls become VNONRELOC expressions (as its result comes +** fixed in the base register of the call), while vararg expressions +** become VRELOCABLE (as OP_VARARG puts its results where it wants). +** (Calls are created returning one result, so that does not need +** to be fixed.) +*/ +void luaK_setoneret (FuncState *fs, expdesc *e) { + if (e->k == VCALL) { /* expression is an open function call? */ + /* already returns 1 value */ + lua_assert(GETARG_C(getinstruction(fs, e)) == 2); + e->k = VNONRELOC; /* result has fixed position */ + e->u.info = GETARG_A(getinstruction(fs, e)); + } + else if (e->k == VVARARG) { + SETARG_B(getinstruction(fs, e), 2); + e->k = VRELOCABLE; /* can relocate its simple result */ + } +} + + +/* +** Ensure that expression 'e' is not a variable. +*/ +void luaK_dischargevars (FuncState *fs, expdesc *e) { + switch (e->k) { + case VLOCAL: { /* already in a register */ + e->k = VNONRELOC; /* becomes a non-relocatable value */ + break; + } + case VUPVAL: { /* move value to some (pending) register */ + e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0); + e->k = VRELOCABLE; + break; + } + case VINDEXED: { + OpCode op; + freereg(fs, e->u.ind.idx); + if (e->u.ind.vt == VLOCAL) { /* is 't' in a register? */ + freereg(fs, e->u.ind.t); + op = OP_GETTABLE; + } + else { + lua_assert(e->u.ind.vt == VUPVAL); + op = OP_GETTABUP; /* 't' is in an upvalue */ + } + e->u.info = luaK_codeABC(fs, op, 0, e->u.ind.t, e->u.ind.idx); + e->k = VRELOCABLE; + break; + } + case VVARARG: case VCALL: { + luaK_setoneret(fs, e); + break; + } + default: break; /* there is one value available (somewhere) */ + } +} + + +/* +** Ensures expression value is in register 'reg' (and therefore +** 'e' will become a non-relocatable expression). +*/ +static void discharge2reg (FuncState *fs, expdesc *e, int reg) { + luaK_dischargevars(fs, e); + switch (e->k) { + case VNIL: { + luaK_nil(fs, reg, 1); + break; + } + case VFALSE: case VTRUE: { + luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0); + break; + } + case VK: { + luaK_codek(fs, reg, e->u.info); + break; + } + case VKFLT: { + luaK_codek(fs, reg, luaK_numberK(fs, e->u.nval)); + break; + } + case VKINT: { + luaK_codek(fs, reg, luaK_intK(fs, e->u.ival)); + break; + } + case VRELOCABLE: { + Instruction *pc = &getinstruction(fs, e); + SETARG_A(*pc, reg); /* instruction will put result in 'reg' */ + break; + } + case VNONRELOC: { + if (reg != e->u.info) + luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0); + break; + } + default: { + lua_assert(e->k == VJMP); + return; /* nothing to do... */ + } + } + e->u.info = reg; + e->k = VNONRELOC; +} + + +/* +** Ensures expression value is in any register. +*/ +static void discharge2anyreg (FuncState *fs, expdesc *e) { + if (e->k != VNONRELOC) { /* no fixed register yet? */ + luaK_reserveregs(fs, 1); /* get a register */ + discharge2reg(fs, e, fs->freereg-1); /* put value there */ + } +} + + +static int code_loadbool (FuncState *fs, int A, int b, int jump) { + luaK_getlabel(fs); /* those instructions may be jump targets */ + return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump); +} + + +/* +** check whether list has any jump that do not produce a value +** or produce an inverted value +*/ +static int need_value (FuncState *fs, int list) { + for (; list != NO_JUMP; list = getjump(fs, list)) { + Instruction i = *getjumpcontrol(fs, list); + if (GET_OPCODE(i) != OP_TESTSET) return 1; + } + return 0; /* not found */ +} + + +/* +** Ensures final expression result (including results from its jump +** lists) is in register 'reg'. +** If expression has jumps, need to patch these jumps either to +** its final position or to "load" instructions (for those tests +** that do not produce values). +*/ +static void exp2reg (FuncState *fs, expdesc *e, int reg) { + discharge2reg(fs, e, reg); + if (e->k == VJMP) /* expression itself is a test? */ + luaK_concat(fs, &e->t, e->u.info); /* put this jump in 't' list */ + if (hasjumps(e)) { + int final; /* position after whole expression */ + int p_f = NO_JUMP; /* position of an eventual LOAD false */ + int p_t = NO_JUMP; /* position of an eventual LOAD true */ + if (need_value(fs, e->t) || need_value(fs, e->f)) { + int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs); + p_f = code_loadbool(fs, reg, 0, 1); + p_t = code_loadbool(fs, reg, 1, 0); + luaK_patchtohere(fs, fj); + } + final = luaK_getlabel(fs); + patchlistaux(fs, e->f, final, reg, p_f); + patchlistaux(fs, e->t, final, reg, p_t); + } + e->f = e->t = NO_JUMP; + e->u.info = reg; + e->k = VNONRELOC; +} + + +/* +** Ensures final expression result (including results from its jump +** lists) is in next available register. +*/ +void luaK_exp2nextreg (FuncState *fs, expdesc *e) { + luaK_dischargevars(fs, e); + freeexp(fs, e); + luaK_reserveregs(fs, 1); + exp2reg(fs, e, fs->freereg - 1); +} + + +/* +** Ensures final expression result (including results from its jump +** lists) is in some (any) register and return that register. +*/ +int luaK_exp2anyreg (FuncState *fs, expdesc *e) { + luaK_dischargevars(fs, e); + if (e->k == VNONRELOC) { /* expression already has a register? */ + if (!hasjumps(e)) /* no jumps? */ + return e->u.info; /* result is already in a register */ + if (e->u.info >= fs->nactvar) { /* reg. is not a local? */ + exp2reg(fs, e, e->u.info); /* put final result in it */ + return e->u.info; + } + } + luaK_exp2nextreg(fs, e); /* otherwise, use next available register */ + return e->u.info; +} + + +/* +** Ensures final expression result is either in a register or in an +** upvalue. +*/ +void luaK_exp2anyregup (FuncState *fs, expdesc *e) { + if (e->k != VUPVAL || hasjumps(e)) + luaK_exp2anyreg(fs, e); +} + + +/* +** Ensures final expression result is either in a register or it is +** a constant. +*/ +void luaK_exp2val (FuncState *fs, expdesc *e) { + if (hasjumps(e)) + luaK_exp2anyreg(fs, e); + else + luaK_dischargevars(fs, e); +} + + +/* +** Ensures final expression result is in a valid R/K index +** (that is, it is either in a register or in 'k' with an index +** in the range of R/K indices). +** Returns R/K index. +*/ +int luaK_exp2RK (FuncState *fs, expdesc *e) { + luaK_exp2val(fs, e); + switch (e->k) { /* move constants to 'k' */ + case VTRUE: e->u.info = boolK(fs, 1); goto vk; + case VFALSE: e->u.info = boolK(fs, 0); goto vk; + case VNIL: e->u.info = nilK(fs); goto vk; + case VKINT: e->u.info = luaK_intK(fs, e->u.ival); goto vk; + case VKFLT: e->u.info = luaK_numberK(fs, e->u.nval); goto vk; + case VK: + vk: + e->k = VK; + if (e->u.info <= MAXINDEXRK) /* constant fits in 'argC'? */ + return RKASK(e->u.info); + else break; + default: break; + } + /* not a constant in the right range: put it in a register */ + return luaK_exp2anyreg(fs, e); +} + + +/* +** Generate code to store result of expression 'ex' into variable 'var'. +*/ +void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) { + switch (var->k) { + case VLOCAL: { + freeexp(fs, ex); + exp2reg(fs, ex, var->u.info); /* compute 'ex' into proper place */ + return; + } + case VUPVAL: { + int e = luaK_exp2anyreg(fs, ex); + luaK_codeABC(fs, OP_SETUPVAL, e, var->u.info, 0); + break; + } + case VINDEXED: { + OpCode op = (var->u.ind.vt == VLOCAL) ? OP_SETTABLE : OP_SETTABUP; + int e = luaK_exp2RK(fs, ex); + luaK_codeABC(fs, op, var->u.ind.t, var->u.ind.idx, e); + break; + } + default: lua_assert(0); /* invalid var kind to store */ + } + freeexp(fs, ex); +} + + +/* +** Emit SELF instruction (convert expression 'e' into 'e:key(e,'). +*/ +void luaK_self (FuncState *fs, expdesc *e, expdesc *key) { + int ereg; + luaK_exp2anyreg(fs, e); + ereg = e->u.info; /* register where 'e' was placed */ + freeexp(fs, e); + e->u.info = fs->freereg; /* base register for op_self */ + e->k = VNONRELOC; /* self expression has a fixed register */ + luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */ + luaK_codeABC(fs, OP_SELF, e->u.info, ereg, luaK_exp2RK(fs, key)); + freeexp(fs, key); +} + + +/* +** Negate condition 'e' (where 'e' is a comparison). +*/ +static void negatecondition (FuncState *fs, expdesc *e) { + Instruction *pc = getjumpcontrol(fs, e->u.info); + lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET && + GET_OPCODE(*pc) != OP_TEST); + SETARG_A(*pc, !(GETARG_A(*pc))); +} + + +/* +** Emit instruction to jump if 'e' is 'cond' (that is, if 'cond' +** is true, code will jump if 'e' is true.) Return jump position. +** Optimize when 'e' is 'not' something, inverting the condition +** and removing the 'not'. +*/ +static int jumponcond (FuncState *fs, expdesc *e, int cond) { + if (e->k == VRELOCABLE) { + Instruction ie = getinstruction(fs, e); + if (GET_OPCODE(ie) == OP_NOT) { + fs->pc--; /* remove previous OP_NOT */ + return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond); + } + /* else go through */ + } + discharge2anyreg(fs, e); + freeexp(fs, e); + return condjump(fs, OP_TESTSET, NO_REG, e->u.info, cond); +} + + +/* +** Emit code to go through if 'e' is true, jump otherwise. +*/ +void luaK_goiftrue (FuncState *fs, expdesc *e) { + int pc; /* pc of new jump */ + luaK_dischargevars(fs, e); + switch (e->k) { + case VJMP: { /* condition? */ + negatecondition(fs, e); /* jump when it is false */ + pc = e->u.info; /* save jump position */ + break; + } + case VK: case VKFLT: case VKINT: case VTRUE: { + pc = NO_JUMP; /* always true; do nothing */ + break; + } + default: { + pc = jumponcond(fs, e, 0); /* jump when false */ + break; + } + } + luaK_concat(fs, &e->f, pc); /* insert new jump in false list */ + luaK_patchtohere(fs, e->t); /* true list jumps to here (to go through) */ + e->t = NO_JUMP; +} + + +/* +** Emit code to go through if 'e' is false, jump otherwise. +*/ +void luaK_goiffalse (FuncState *fs, expdesc *e) { + int pc; /* pc of new jump */ + luaK_dischargevars(fs, e); + switch (e->k) { + case VJMP: { + pc = e->u.info; /* already jump if true */ + break; + } + case VNIL: case VFALSE: { + pc = NO_JUMP; /* always false; do nothing */ + break; + } + default: { + pc = jumponcond(fs, e, 1); /* jump if true */ + break; + } + } + luaK_concat(fs, &e->t, pc); /* insert new jump in 't' list */ + luaK_patchtohere(fs, e->f); /* false list jumps to here (to go through) */ + e->f = NO_JUMP; +} + + +/* +** Code 'not e', doing constant folding. +*/ +static void codenot (FuncState *fs, expdesc *e) { + luaK_dischargevars(fs, e); + switch (e->k) { + case VNIL: case VFALSE: { + e->k = VTRUE; /* true == not nil == not false */ + break; + } + case VK: case VKFLT: case VKINT: case VTRUE: { + e->k = VFALSE; /* false == not "x" == not 0.5 == not 1 == not true */ + break; + } + case VJMP: { + negatecondition(fs, e); + break; + } + case VRELOCABLE: + case VNONRELOC: { + discharge2anyreg(fs, e); + freeexp(fs, e); + e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0); + e->k = VRELOCABLE; + break; + } + default: lua_assert(0); /* cannot happen */ + } + /* interchange true and false lists */ + { int temp = e->f; e->f = e->t; e->t = temp; } + removevalues(fs, e->f); /* values are useless when negated */ + removevalues(fs, e->t); +} + + +/* +** Create expression 't[k]'. 't' must have its final result already in a +** register or upvalue. +*/ +void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) { + lua_assert(!hasjumps(t) && (vkisinreg(t->k) || t->k == VUPVAL)); + t->u.ind.t = t->u.info; /* register or upvalue index */ + t->u.ind.idx = luaK_exp2RK(fs, k); /* R/K index for key */ + t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL : VLOCAL; + t->k = VINDEXED; +} + + +/* +** Return false if folding can raise an error. +** Bitwise operations need operands convertible to integers; division +** operations cannot have 0 as divisor. +*/ +static int validop (int op, TValue *v1, TValue *v2) { + switch (op) { + case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR: + case LUA_OPSHL: case LUA_OPSHR: case LUA_OPBNOT: { /* conversion errors */ + lua_Integer i; + return (tointeger(v1, &i) && tointeger(v2, &i)); + } + case LUA_OPDIV: case LUA_OPIDIV: case LUA_OPMOD: /* division by 0 */ + return (nvalue(v2) != 0); + default: return 1; /* everything else is valid */ + } +} + + +/* +** Try to "constant-fold" an operation; return 1 iff successful. +** (In this case, 'e1' has the final result.) +*/ +static int constfolding (FuncState *fs, int op, expdesc *e1, + const expdesc *e2) { + TValue v1, v2, res; + if (!tonumeral(e1, &v1) || !tonumeral(e2, &v2) || !validop(op, &v1, &v2)) + return 0; /* non-numeric operands or not safe to fold */ + luaO_arith(fs->ls->L, op, &v1, &v2, &res); /* does operation */ + if (ttisinteger(&res)) { + e1->k = VKINT; + e1->u.ival = ivalue(&res); + } + else { /* folds neither NaN nor 0.0 (to avoid problems with -0.0) */ + lua_Number n = fltvalue(&res); + if (luai_numisnan(n) || n == 0) + return 0; + e1->k = VKFLT; + e1->u.nval = n; + } + return 1; +} + + +/* +** Emit code for unary expressions that "produce values" +** (everything but 'not'). +** Expression to produce final result will be encoded in 'e'. +*/ +static void codeunexpval (FuncState *fs, OpCode op, expdesc *e, int line) { + int r = luaK_exp2anyreg(fs, e); /* opcodes operate only on registers */ + freeexp(fs, e); + e->u.info = luaK_codeABC(fs, op, 0, r, 0); /* generate opcode */ + e->k = VRELOCABLE; /* all those operations are relocatable */ + luaK_fixline(fs, line); +} + + +/* +** Emit code for binary expressions that "produce values" +** (everything but logical operators 'and'/'or' and comparison +** operators). +** Expression to produce final result will be encoded in 'e1'. +** Because 'luaK_exp2RK' can free registers, its calls must be +** in "stack order" (that is, first on 'e2', which may have more +** recent registers to be released). +*/ +static void codebinexpval (FuncState *fs, OpCode op, + expdesc *e1, expdesc *e2, int line) { + int rk2 = luaK_exp2RK(fs, e2); /* both operands are "RK" */ + int rk1 = luaK_exp2RK(fs, e1); + freeexps(fs, e1, e2); + e1->u.info = luaK_codeABC(fs, op, 0, rk1, rk2); /* generate opcode */ + e1->k = VRELOCABLE; /* all those operations are relocatable */ + luaK_fixline(fs, line); +} + + +/* +** Emit code for comparisons. +** 'e1' was already put in R/K form by 'luaK_infix'. +*/ +static void codecomp (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) { + int rk1 = (e1->k == VK) ? RKASK(e1->u.info) + : check_exp(e1->k == VNONRELOC, e1->u.info); + int rk2 = luaK_exp2RK(fs, e2); + freeexps(fs, e1, e2); + switch (opr) { + case OPR_NE: { /* '(a ~= b)' ==> 'not (a == b)' */ + e1->u.info = condjump(fs, OP_EQ, 0, rk1, rk2); + break; + } + case OPR_GT: case OPR_GE: { + /* '(a > b)' ==> '(b < a)'; '(a >= b)' ==> '(b <= a)' */ + OpCode op = cast(OpCode, (opr - OPR_NE) + OP_EQ); + e1->u.info = condjump(fs, op, 1, rk2, rk1); /* invert operands */ + break; + } + default: { /* '==', '<', '<=' use their own opcodes */ + OpCode op = cast(OpCode, (opr - OPR_EQ) + OP_EQ); + e1->u.info = condjump(fs, op, 1, rk1, rk2); + break; + } + } + e1->k = VJMP; +} + + +/* +** Apply prefix operation 'op' to expression 'e'. +*/ +void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) { + static const expdesc ef = {VKINT, {0}, NO_JUMP, NO_JUMP}; + switch (op) { + case OPR_MINUS: case OPR_BNOT: /* use 'ef' as fake 2nd operand */ + if (constfolding(fs, op + LUA_OPUNM, e, &ef)) + break; + /* FALLTHROUGH */ + case OPR_LEN: + codeunexpval(fs, cast(OpCode, op + OP_UNM), e, line); + break; + case OPR_NOT: codenot(fs, e); break; + default: lua_assert(0); + } +} + + +/* +** Process 1st operand 'v' of binary operation 'op' before reading +** 2nd operand. +*/ +void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) { + switch (op) { + case OPR_AND: { + luaK_goiftrue(fs, v); /* go ahead only if 'v' is true */ + break; + } + case OPR_OR: { + luaK_goiffalse(fs, v); /* go ahead only if 'v' is false */ + break; + } + case OPR_CONCAT: { + luaK_exp2nextreg(fs, v); /* operand must be on the 'stack' */ + break; + } + case OPR_ADD: case OPR_SUB: + case OPR_MUL: case OPR_DIV: case OPR_IDIV: + case OPR_MOD: case OPR_POW: + case OPR_BAND: case OPR_BOR: case OPR_BXOR: + case OPR_SHL: case OPR_SHR: { + if (!tonumeral(v, NULL)) + luaK_exp2RK(fs, v); + /* else keep numeral, which may be folded with 2nd operand */ + break; + } + default: { + luaK_exp2RK(fs, v); + break; + } + } +} + + +/* +** Finalize code for binary operation, after reading 2nd operand. +** For '(a .. b .. c)' (which is '(a .. (b .. c))', because +** concatenation is right associative), merge second CONCAT into first +** one. +*/ +void luaK_posfix (FuncState *fs, BinOpr op, + expdesc *e1, expdesc *e2, int line) { + switch (op) { + case OPR_AND: { + lua_assert(e1->t == NO_JUMP); /* list closed by 'luK_infix' */ + luaK_dischargevars(fs, e2); + luaK_concat(fs, &e2->f, e1->f); + *e1 = *e2; + break; + } + case OPR_OR: { + lua_assert(e1->f == NO_JUMP); /* list closed by 'luK_infix' */ + luaK_dischargevars(fs, e2); + luaK_concat(fs, &e2->t, e1->t); + *e1 = *e2; + break; + } + case OPR_CONCAT: { + luaK_exp2val(fs, e2); + if (e2->k == VRELOCABLE && + GET_OPCODE(getinstruction(fs, e2)) == OP_CONCAT) { + lua_assert(e1->u.info == GETARG_B(getinstruction(fs, e2))-1); + freeexp(fs, e1); + SETARG_B(getinstruction(fs, e2), e1->u.info); + e1->k = VRELOCABLE; e1->u.info = e2->u.info; + } + else { + luaK_exp2nextreg(fs, e2); /* operand must be on the 'stack' */ + codebinexpval(fs, OP_CONCAT, e1, e2, line); + } + break; + } + case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV: + case OPR_IDIV: case OPR_MOD: case OPR_POW: + case OPR_BAND: case OPR_BOR: case OPR_BXOR: + case OPR_SHL: case OPR_SHR: { + if (!constfolding(fs, op + LUA_OPADD, e1, e2)) + codebinexpval(fs, cast(OpCode, op + OP_ADD), e1, e2, line); + break; + } + case OPR_EQ: case OPR_LT: case OPR_LE: + case OPR_NE: case OPR_GT: case OPR_GE: { + codecomp(fs, op, e1, e2); + break; + } + default: lua_assert(0); + } +} + + +/* +** Change line information associated with current position. +*/ +void luaK_fixline (FuncState *fs, int line) { + fs->f->lineinfo[fs->pc - 1] = line; +} + + +/* +** Emit a SETLIST instruction. +** 'base' is register that keeps table; +** 'nelems' is #table plus those to be stored now; +** 'tostore' is number of values (in registers 'base + 1',...) to add to +** table (or LUA_MULTRET to add up to stack top). +*/ +void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) { + int c = (nelems - 1)/LFIELDS_PER_FLUSH + 1; + int b = (tostore == LUA_MULTRET) ? 0 : tostore; + lua_assert(tostore != 0 && tostore <= LFIELDS_PER_FLUSH); + if (c <= MAXARG_C) + luaK_codeABC(fs, OP_SETLIST, base, b, c); + else if (c <= MAXARG_Ax) { + luaK_codeABC(fs, OP_SETLIST, base, b, 0); + codeextraarg(fs, c); + } + else + luaX_syntaxerror(fs->ls, "constructor too long"); + fs->freereg = base + 1; /* free registers with list values */ +} + |